Schwarzschild black hole embedded in a dust field: scattering of particles and drag force effects

TL;DR

This paper studies how dust around a Schwarzschild black hole affects particle motion, introducing a drag force that alters trajectories and can create stable orbits, differing from pure geodesic paths.

Contribution

It introduces a novel analysis of dust-induced friction effects on particles near a Schwarzschild black hole, extending the understanding of accretion and scattering processes.

Findings

Particles experience acceleration due to dust-induced friction.

Equilibrium orbits can form, preventing infall or escape.

Dust effects significantly alter particle trajectories.

Abstract

A "temporal analogue" of the standard Poynting-Robertson effect is analyzed as induced by a dust of particles (instead of a gas of photons) surrounding a Schwarzschild black hole. Test particles inside this cloud undergo acceleration effects due to the presence of a friction force, so that the fate of their evolution can be completely different from the corresponding geodesic motion. Typical situations are discussed of hyperbolic motion of particles scattered by the black hole in the presence of a dust filling the whole spacetime region outside the horizon as well as particles which free fall radially crossing a corona located at a certain distance from the horizon. The existence of equilibrium orbits may prevent particles from either falling into the hole or escaping to infinity.